Electromagnetic actuator



pml 3179 Q WQ H, @ILLE 2999@ ELTRMAGNTIC CTUTQR Filed. Nov. 16, 3.949

Z'mventor WILLIS H. GILLE Gttorneg Patented Apr. 17, :1951

UNIT/ED ySTATES PATENT OFFICE .ELECTROMAGNETIC ACTUATOR Willis H. Gille, St. Paul, Minn., assigner to Minneapolis-Honeywell Regulator Company`Min neapolis, Minn., a corporation 0f Delaware .Application-Novcmber 16, 1949,'Serial No. 127,607

2 Claims. r1

Myr invention relates to electromagnetic. actuators and more .particularly to improvements rin actuators of the pivoted armature and plunger type which substantially eliminate the noise of operation of the actuator and rebound of the armature or plunger.

While actuators .of the pivoted armature or movable plunger type are old,.they generally have a common disadvantage in that the engagement of the armature with .a cooperating .core or a plunger with a cooperating stop` elementproduces undesirable noise and sets up a tendency for the armature to lrebound thereby adversely affecting its` controlling. operation. The present invention provides in anactuator of this type a core struc- 'ture havinga magnetic circuit in which a portion to be engaged bythe armature upon magnetic attraction between the armatureand core structure is movable relativeto the remainder of the circuit without introducing any substantial variation in lthe magneticcircuit to effect continuous attraction between the parts and elimination of the shock and noise ofV operation.

It is therefore an object of this invention to provide a simplified and improved electromagnetic Aactuator in .which noise of operation and rebound is absorbed.

It is also an objectof thisinvention to provide asimpliedstop structure for an electromagnetic actuator in which attraction between the parts remains .unchanged uponoperation. of the device.

TheseV and other objects ofrthis invention will become apparent from a` readingof the attached specification and together .Withthe drawings in "Figure 1 is a plan view of the electromagnetic m3133012 Fsurei2 isa section of the plan View. of Figure 1 showing thevrelationshipof parts,

Figure 3 is a side elevation view in section of the actuator, and

Figure 4 is a side `elevation view of another embodiment of this invention Ashown in section and disclosing therrelationship of the parts.

improved electromagnetic actuator is shown in the drawings in the form of a. clapper-type electromagnet or relayhaving a magnetic core structure which y includesa stationary core member if), generally' Leshaped iny form having a main or base portion I I with a plurality of upstanding or transversely extending portions I2, I3. The upstandine portions I2, I3 are separated into a centrally located portion I Zvuponwhich an.arma. ture 151s'adaptedtobepivoted and a pair of side portions I3 which serve as. b-ackstops `for .the

armature in a manner later to be described. Magnetic core structure Il) including the main portion il and'upstanding portions I2 andI3 yas well as armature Ie51are made of amagnetic ma terialof relatively good permeability, such as. soft iron, to provide a continuous magnetic circuit.

Armature .l5is generallybar-shaped inform and has attached thereto at its pivoted. extremity a. brasszmounting plateflfwhich issecured. to the armature I5 through rivets Il and areinforcing plate i3, all piecesbeing made of anon-magnetic material. As best shown in'Figures 1 andf2,-the non-magnetic` mounting .plate ll6 has .afpair lof notchesil'therein and a,centrallylocatedapen` ture?! the purposes of ,whichwillbecome evident as the disclosure proceeds. vNotches 20 of -plate It receive projecting guide members 22 of `a mounting plate 2-3iwhich1is attachedfto upstanding portion I2 of core member I0. Mounting plate 2,3is attached to-vupstanding portion I2by any suitable means, such kas by rivets, and may be made of any material such asiron or brass. Plate 23withthe exception of the guide pins 22, is so positioned on the upstanding member lf2 that it terminates belowthe upper -edge'of the upstanding portion |12 sor-as not fto be Vlin contact with the armature'l5. Theprojecting guides .2v2 are disposed to one or fthe other side of thelmain bodyvof therarmature I5Yand fit intofthe slotsi in the brass mounting'plate kI Bftoguide the armature in its pivotal movement The-upstanding portion I2 ofthe core structure Ill is beveled as-at 25 and engages the armature I5 ina knife-edge engagement. As previously noted, brass 1mounting plate I6 has -a centrally located lnotch on aperture 2I so-provided that the upstandingportion 'lf2 of core structure I0 can directly engage the armatureV I5 to providea-continuous-magnetic circuit at this point.

The lower extremity of mountlngplate23 has a transversely extending flange 25 designed "to receive and anchor one end of a-spring 21, the opposite extremity -of which is anchored in a notch or aperture-28 inthe extremity of armature l5. In this .manner the `armature y-I5 is biased toan open positionor biased for counterclockwise movement about the pivot formed between the upstanding portion I2 vand thefarmature :|5, project up to substantially the same level as the centrallylocated. supstanding'portion I2 and are spacedto receive fthe extremity of theiarmature to provide va backstoptherefor. Further, these porti-ons .ci the .core structure provide ,fa parallel magnetic circuit for-the .core structure Side sections I3 of the core structure which is continuous or without an air gap when the up armature is in an open or deenergized position.

Armature I5 at its free extremity carries a plunger 30 made of a plurality of laminations of magnetic material and attached to the armature proper by means of rivets 3 I. Plunger 30 extends transversely of the main body of armature I5 and carries a short circuited conductor or shading coil 32 embedded in its free extremity. The plunger 3l) is further disposed within the coniines of a coil 33 mounted on an insulating bobbin 34 and secured to the main body portion II of core structure ID. Coil 33 is mounted on the main portion I I of core structure IU by means of a brass sleeve 35 which extends through an aperture 36 in the portionv II of core structure I 0, the sleeve being turned or crimped over at its extremities to securely mount the coil to the core structure I and align the coil with the aperture 35 and armature plunger 30. The magnetic circuit for core structure IU is completed from the plunger 30 of armature I5 through a magnetic bridging member 40 disposed concentrically with the aperture 36 in portion II of the core member and abutting against the core member at its raised edge 4I. Bridging plate 40 is mounted on the core structure II) by means of a spring member 42 to which the plate is riveted as at 43. The free extremity of spring 42 is secured to the portion II of the L-shaped core member I l) by means of a screw 44 which is threaded into the core member. A spacer 45 is provided between the spring and core member such that the spring will urge the bridging plate into engagement with the core member I I at all proportions of the raised surface 4I.

In operation, the energization of coil 33 sets up flux lines within the magnetic circuit of the core structure which traversed the magnetic circuit through the plunger 30, armature I5, the upstanding portions I2, I3 of the core structure, the main portion II of the core structure, the bridging plate 40, and through the air gap back to the plunger 30. A magnetic attraction will be set up by the circulating flux lines such that the armature I and plunger 30 will be drawn further into the confines of coil 33 until it engages the stop member 4D. As the plunger 3D travels toward its energized position, the force of attraction between the stationary and movable parts of the magnetic circuit is increased and the momentum of the plunger and armature as it engages bridging plate 40 will cause this bridging plate to move away from contact with the main portion of the core structure. In so moving, the bridging plate will substantially absorb the momentum and noise of engagement of the plunger with itself and the plunger will continue to be attracted to the bridging member. lIfhis magnetic attraction between the plunger and bridging plate will cause the plunger to remain in engagement with the bridging plate and hence the armature in the energized position of the actuator as the momentum is absorbed and the plate returns to its normal position. Shading coil 32 carried by the plunger 30 operates in the conventional manner to set out an out-ofphase iiux such that an A. C. hum or chatter caused by the A. C. energization of the coil will be overcome. Displacement of the bridging plate 30 from core member IIJ is not of suicient magnitude to vary the characteristics, that is, the reluctance of' the magnetic circuit substantially, and hence continuous attraction of the plunger is obtained thereby eliminating any rebound other than the movement of the plate and plunger back to the normally energized position wherein the bridging plate 40 is in contact with the core structure I0.

Species of Figure 3 The embodiment shown in Figure 3 is similar to that of Figure 2 with the-exception of the arrangement of the bridging plate and the modication of plunger 5I of the armature I5. Bridging plate 50 takes the form of a multi-part bridging or stop member having a plurality of inner bridging plates 53 one edge 56 of each of which is positioned in notches 5l in the lower portion of core structure I0 and an outer bridging plate 54, the outer bridging plate being riveted to the spring member 42 which in turn is mounted on the core structure I0 through the screws 44 and spacer 45 in the manner described in connection with Figure 1.

Plunger member 5I which is attached to armature I5 of the actuator is similar to plunger 30 being made of a plurality of laminations of magnetic material riveted together and attached to the armature through rivets 3l. Plunger 5I differs from plunger 5l), as can be seen in Figure 3, in that a central extended portion of the plunger 5|, encircled by the shading means 32, is extended for reasons which will be later noted.

In operation, the actuator of Figure 3 operates in a manner similar to that of Figure 2 differing therefrom only in the fact that the inner stop members 53 operate to maintain continuous engagement of the bridging plate with the core member II after plunger 5I engages the bridging plate 5U. The bridging plates or stop members 53 are separated to provide an opening through which the central or extended portion 55 of the plunger 5I extends as the plunger is drawn further into the connes of coil 33. This extended portion strikes the outer bridging plate 54 and at the same time the remaining portion of the plunger engages the plurality of stop members 53 to rock those members within the notches or guides 51 with respect to the core maintaining contact between the core member I I and the bridging plates 53, 54. .In this manner a continuous circuit is obtained and no further air gap is inserted in the magnetic circuit. The bridging plates 53 are held in position with respect to the magnetic core structure by virtue of the edges 56 within the notches 5l and the biasing effect of outer plate 54 through the operation of spring 42. This stop member similarly absorbs the momentum and noise of engagement between the armature and the remaining portion of the core structure providing for substantially maximum magnetic attraction between the Vstationary and movable portions of the magnetic circuit.

While the disclosure herein is related to pivoted armature type actuators and the present teaching is particularly applicable to such an actuator, it is to be understood that a simple plunger type actuator with an appropriate magnetic core structure can utilize the teaching herein by a substitution of the movable stop member for the conventional stationary type'stop. The present disclosure is, however, intended to be illustrative only and the scope of the subject invention is to be determined only by the appended claims.

I claim:

1. In an electromagnetic actuator, a magnetic core structure including a core member having an upstanding portion and a transversely extending portion'with an aperture in said transversely standing portion of said core member with said plunger of said armature means moving within the confines of said hollow coil and out of physical contact therewith, a plate of magnetic material positioned in bridging relationship over said aperture in said transversely extending portion of said core member, means including a spring of nonmagnetic material mounting said plate on said Y transversely extending portion of said core member for movement relative thereto, said core structure being energized with a magnetic iiux which flows through said core member said armature means and said plate causing said plunger to be attracted toward and into engagement with said plate, said mounting means for said plate permitting movement of said plate relative to said core member to absorb the impact of said engagement in such a manner that the .bridging relationship and the magnetic flux flow within said core structure is substantially maintained.

2. In an electromagnetic actuator, a magnetic core structure including a core member having an upstanding portion and a transversely extending portion With an aperture in said transversely extending portion, a hollow energizing coil for energizing said core structure, means including a nonmagnetic sleeve member securing said hollow coil to said core member in alignment with said aperture, armature means including a plate of magnetic material pivotally mounted on said upstanding portion of said core member and a plunger of magnetic material attached at one extremity thereof extending normal to said plate and into the confines of said coil, said armature means being adapted to be pivoted about said upstanding portion of said core member with said plunger of said armature means moving within the connes of said hollow coil and out of physical contact therewith, a plurality of members of magnetic material normally disposed outside of saidaperture in said transversely extending portion of said core member and covering said aperture in a bridging relationship therewith, means mounting said plurality of members on said transversely extending portion of said core member for movement relative thereto, said core structure upon energization of said coil be ing energized with a magneticflux which flows through said core members, said armature means and said plurality of magnetic members causing said plunger to be attracted toward and into engagement with said plurality of magnetic members, said mounting means for said plurality of magnetic members permitting movement of said members relative to said core member upon engagement of said plunger with Said magnetic members to absorb the impact thereof in such a manner that said bridging relationship and ow of ilux through said core structure is substantially maintained.

. WILLIS H. GILLE.

REFERENCES CITED The following references are of record in the ile of this patent:

UN'TED STATES PATENTS 

